Variation in diversity among Laurales, Early Cretaceous to Present
نویسنده
چکیده
Species accumulation and extinction both take time, and the asymmetry between the two processes has long been recognized (Darwin 1859). Darwin argued that complete extinction would take longer than species accumulation, except in the case of catastrophic mass extinctions. “There is reason to believe that the complete extinction of the species of a group is generally a slower process than their production: if the appearance and disappearance of a group of species be represented, as before, by a vertical line of varying thickness, the line is found to taper more gradually at its upper end, which marks the progress of extermination, than at its lower end, which marks the first appearance and increase in numbers of the BS 55 441
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